An arena has 20 people seated in Section 1, 35 people in Section 2, 50 people in Section 3, and so on for each of its section. Which section of the arena holds exactly 320 people
I know it goes up by 15 each time so instead of starting at 20 I started at 15 and 15 times 21 is 315 then I added the five again to get 320 so answer 21
